The present invention relates to a safety road barrier end assembly specifically designed for safely operating and provided with a gradual absorption of the impact energy.
As is known, urban, extra-urban roads and highways have a lot of dangerous points including rigid obstacles or sloping areas, as well as pedestrian or cyclist passages, which are protected by safety barriers which can be either of a metal or of a concrete type.
The metal road barriers, which are the most diffused protective barriers for all applications, generally comprise a plurality of steel strip segments, provided with xe2x80x9cwavedxe2x80x9d or corrugated cross sections, thereby providing a comparatively high moment of inertia and according a good flexural strength, said barrier segments being conventionally coupled to piers anchored or bolted to the ground.
The above mentioned barriers, owing to an advanced designing in recent years, provide a satisfactory performance for substantially all of the impacts provided by the enforcing standards, in particular by the EPO standards, as the impacts occur at a given point of the extension of the barrier.
However, problems can occur as the vehicle impact affects end portions of said barriers, mainly as said barriers, as it frequently occurs, are not sufficiently spaced in a width direction with respect to the traffic lane.
Actually, conventional metal safety barriers are only provided with end elements or assemblies of a xe2x80x9chandxe2x80x9d or of a xe2x80x9cfanxe2x80x9d type, or they are provided with a corrugated web portion as bent at the ground level.
The first mentioned types of end assemblies, i.e. the so-called xe2x80x9chandxe2x80x9d end or terminal assemblies, or the so-called xe2x80x9cfanxe2x80x9d end assemblies, have a merely visual function, without any strength properties, both of angular and side type, and they are very dangerous for all the front impacts or the angled front impacts, since the barriers would tend to operate as a tip-impacted beam, with consequent intrusion effects with respect to the motor vehicle.
The second end assembly, i.e. the ground bent end assemblies, are susceptible to frequently cause the impacting motor vehicle to be upturned, with very dangerous consequences.
Yet other end assemblies for barriers, designed for other traffic and motor vehicle types, for example those used on USA safety barriers, are very complex and expensive and do not properly operate under the typical conditions of the European and Italian roads characterized by a high speed traffic, as well as by a disordered traffic with a higher proportion of light vehicles.
In this connection reference is herein made to the U.S. Pat. No. 5,078,366 in the name of Sicking et al, disclosing a safety road barrier end assembly provided with a specifically designed head adapted to extrude the guardrail strip so as to provide a xe2x80x9cloopxe2x80x9d of a comparatively large size, and the PCT application WO 96/13972 to Sicking et al, disclosing a safety barrier end assembly including a head portion having a plurality of knife elements designed for longitudinally cutting the strip, thereby weakening it and favoring the so-called xe2x80x9cbucklingxe2x80x9d effect.
Accordingly, the aim of the present invention is to overcome the above mentioned problems, by providing a road safety barrier having suitable safety properties and which is specifically designed to meed the enforcing standards by gradually absorbing the motor vehicle impact energy, thereby reducing the impact effects on the motor vehicle and on the persons therein.
Within the scope of the above aim, a main object of the present invention is to provide an end assembly for a safety road barrier, having very high strength characteristics, both under mainly longitudinal impacts and under mainly lateral impacts.
Another object of the present invention is to provide such an end assembly for safety road barriers, which can be easily assembled and used together with the existing metal road barriers.
Yet another object of the present invention is to provide such a road barrier end assembly which can be easily made starting from easily available elements and materials and which, moreover, is very competitive from a mere economic standpoint.
According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a safety road barrier end assembly provided with a gradual absorption of an impact energy, characterized in that said end assembly comprises grooved corrugated elements coupled. to a front side facing a road of supporting piers, said corrugated elements being coupled to said supporting piers by sliding coupling means, for causing a friction and plastic deformation of said slots in a direction parallel to a longitudinal extension of said barrier, anchoring means for anchoring said supporting piers to a ground being moreover provided.
The absorption of the impact energy in a longitudinal direction of the barrier occurs mainly by a plastic deformation of the metal forming the corrugated elements and, more specifically, by a variation of the shape and size of the longitudinal slots in said elements, by the sliding elements rigid with the supporting piers.